Latch mechanism



y 1954 R. E. JOHNSON 2,679,424

LATCH MECHANISM Filed Feb. 5, 1952 3 Sheets-Sheet 1 INVENTOR.

y 1954 R. E. JOHNSON 2,679,424

LATCH MECHANISM Filed Feb. 5, 1952 3 Sheets-Sheet 2 INVENTOR.

y 1954 R. E. JOHNSON 2,679,424

LATCH MECHANISM Filed Feb. 5, 1952 5 Sheets-Sheet 3 V I v i 32 j Z HIII \I 5/ 5: H Tfi'x 1 Z 3.5 I 30 I '7. MI]. IHIII 20 M 1%,, M; U: f I

Patented May 25, 1954 LATCH MECHANISM Robert E. Johnson, Marne, Mich., assignor to Jervis Corporation, Grandville, Mich., a corporation of Michigan Application February 5, 1952, Serial No. 269,925

7 Claims.

This invention relates to a latch mechanism and it is an object of the invention to provide improved apparatus of that character.

A latch mechanism constructed in accordance with the invention may be identical in its basic structure to the latch mechanism disclosed and claimed in application Serial No. 151,461 (now abandoned) in the name of Lloyd L. Anderson and Robert E. Johnson filed on March 23, 1950, which application was prior to abandonment continued as Serial No. 270,179 in the name of Robert E. Johnson filed on February 6, 1952; both applications Serial Nos. 151,461 and 270,179 being assigned to the same assignee as the present invention (said assignee has by change of name certificate recorded in the United States Patent Ofiice become Jervis Corporation).

A latch mechanism constructed in accordance with the invention employs a small number of moving parts, and, more specifically, has only two major internal moving parts. At the same time the latch mechanism is one which may cock in its open position and one which exerts a powerful closing force as the mechanism approaches its keeper engaging position, due to a varying leverage or mechanical advantage of the operating parts. The latch mechanism is furthermore one which permits the door with which it cooperates to be slammed shut in the event that the latch mechanism is inadvertently tripped while the door is open. Still further, a latch mechanism constructed in accordance with the invention is very simple in construction while maintaining the operating advantages outlined above.

Accordingly it is another object of the invention to provide an improved cocking latch mechanism.

It is another object of the invention to provide an improved cocking latch mechanism which is readily movable from its keeper engaging posi tion to a keeper by-passing position whereby the latch mechanism permits a door with which it cooperates to be slammed shut in the event that the mechanism is inadvertently tripped while the door is open.

It is another object of the invention to provide an improved latch mechanism having the advantages referred to above while employing a small number of movin parts.

It is another object of the invention to pro vide an improved latch mechanism having the advantages referred to above and having an improved and simplified cam means for effecting the desired operation.

This invention, together with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanyin drawings, and its scope will be pointed out in the appended claims.

In the drawings, in which like parts are designated by like reference numerals,

Fig. 1 is a plan view of a latch mechanism constructed in accordance with the invention, the mechanism being shown in connection with a refrigerator door and cabinet;

Fig. 2 is a plan view of the same latch mechanism with one wall of its supporting frame broken away and omitting the refrigerator door and cabinet, the latch mechanism being shown in a different operating position than in Fig. 1;

Fig. 3 is a plan view of the same latch mechanism with the upper half of the latch mechanism broken away and showingthe latch mechanism in the same operating position as in Fig. 1;

Fig. 4 is a plan view similar to Fig. 2 and showing the latch mechanism in another operating position;

Fig. 5 is a complete side view of the same latch mechanism taken along the line 5-5 of Fig. 2;

and

Fig. 6 is a similar side view taken along the line 66 of Fig. 3.

A latch mechanism constructed in accordance with the invention is particularly adapted for use on refrigerators and the illustrated embodiment is shown in Fig. 1 in such an application. The operating portion In of the latch mechanism is shown mounted on a refrigerator door H, and a cooperating keeper [2 is shown mounted on a refrigerator cabinet 13. The operating portion 10 of the latch mechanism includes a supporting frame I l which is adapted to be secured to the refrigerator door H, as by the screws I5 and IS.

A latch bolt I! having spaced apart, opposed walls is provided which is pivotable about a pin 18, the pin being secured to opposed walls of the supporting frame 14. The latch bolt carries a keeper engagin roller 18 rotatably mounted thereon by a pin 19. The latch bolt is pivotable between a keeper engaging position in which the latch bolt roller I8 may engage the keeper 12, see Fig. 3, and. a cooked position in which the latch bolt roller is so positioned that it may not engage the keeper, see Fig. 2.

An actuator 20 is pivotally mounted on the supporting frame 14 by a pin 2|, and a spring 22 is arranged around the pin 2! and so engages the frame 14 and the'actuator 20 as to urge the actuator in a counterclockwise direction. As may be seen best in Figs. and 6, the actuator 20 is of a double wall construction, the opposed walls lying immediately outside the two walls of the latch bolt.

As may be seen in Fig. 1 an operating handle 25 is pivotally mounted on the door H through a pin 28 and a small housin 21 provided for that purpose. A push rod 28 is arranged between the handle 25 and one portion of the actuator 20 whereby clockwise rotation of the handle 25 results in an inwardly directed force being transmitted to the actuator 20, the latter thereby also being rotated in a clockwise direction about the pivot pin 2|.

A cam surface is provided on the actuator 20 including a recessed portion 30 and a dwell or flattened portion 3|. A cam roller 32 is rotatably mounted on the latch bolt through a pin 33, this cam roller being arranged to cooperate with the cam surfaces 30 and 3| of the actuator 20.

The latch mechanism is shown in its keeper engaging position in Fig. 3 wherein the cam roller 32 engages the recessed portion 30 of the cam surface on the actuator. When the latch bolt I1 is in this keeper engaging position the actuator 20 assumes what may be termed its normal position, the actuator being rotated as far as it may in a counterclockwise direction.

When the handle 25 is operated to rotate the actuator 20 in a clockwise direction, the cam roller 32 is in effect removed from the recessed cam portion 30 and is therefore free to move upwardly with respect to the actuator. A relatively light spring 35 which is wound around the pivot pin it so engages the supporting frame l4 and a tab 36, secured to and preferably struck from the latch bolt II, as to urge the latch bolt to rotate in a clockwise direction about the pin l8. Accordingly, when the actuator 20 has been rotated in a clockwise direction from the position illustrated in Fig. 3 to the position illustrated in Fig. 2, the spring 35 urges the latch bolt I! to rotate in a clockwise direction whereupon the cam roller 32 comes into engagement with the flattened cam surface 3| of the actuator. Such clockwise movement of the latch bolt swings the latch bolt roller l8 away from its keeper engaging position as previously explained, whereupon the door H is free to be opened.

When the handle 25 is released, a lightweight spring, not shown in the drawings, may be employed to return the handle to its normal position, illustrated in Fig. 1, but the latch bolt l1 and the actuator 23 will remain in the positions illustrated in Fig. 2 since they have toggled or cocked in this position. More specifically the flattened cam surface 3| of the actuator engages the cam roller 32 at a point substantially on a line joining the rotational axis of the cam roller 32 and the pivotal axis of the latch bolt Actually it is preferable that the cam surface 3| engage the cam roller 32 at a point minutely below a line joining these axes in order that the latch bolt Il may definitely cock or toggle in the open or cooked position illustrated in Fig. 2.

In actual operation of the latch mechanism the handle 25 is seldom actually twisted by the operator to impart only pivotal movement thereto, but instead the operator normally pulls outwardly on the handle 25, which action tends to draw the door H and the latch mechanism It] away from the cabinet l3 as well as to impart a pivotal movement to the handle 25. Accordingly, as the actuator 20 is moved toward the position illustrated in Fig. 2, and as the cam roller 32 is gradually permitted to ride up out of the recessed cam portion 30, the door I is gradually opened, thereby maintaining the latch bolt roller l8 against the keeper E2. Normally the effective torque applied to the handle 25 by the operator terminates when the latch bolt roller l3 reaches a position in which it may pass by the nose of the keeper, any force continuing to be applied to the handle merely serving to draw the door open. Accordingly, if cocking of the latch is to be assured on each opening of the door it is necessary that the latch bolt i! be in its cocked position when the latch bolt roller l8 will barely clear the nose of the keeper l2. At the same time, however, it is necessary that the latch bolt roller i8 be permitted to move at least a short distance beyond the position in which it will barely clear the nose of the keeper since otherwise no tolerance would be permitted in the relative positioning of the keeper l2 with respect to the latch mechanism l0.

There are at least two obvious solutions to this problem which have definite drawbacks. First, the keeper |2 can be positioned with respect to the latch mechanism In with extreme accuracy. This, of course, is undesirable since it requires a substantial amount of time to make the necessary number of trial settings of the keeper to find the position in which the latch bolt roller l8 may escape from the keeper and the latch bolt still will assuredly be cooked at each opening of the door.

A second solution is to permit the cam elements to pass a substantial distance over center. In this manner any reasonable amount of tolerance in the positioning of the keeper |2 may be permitted since the latch bolt may be made to reach its cocked position while the latch bolt roller still engages the keeper, after which the latch bolt roller may still move a substantial distance to the right in Figs. 1-4 as the latch bolt moves over center. This solution has the definite disadvantage that a very substantial force is required to trip the latch bolt, that is to move the latch bolt and more specifically the cam elements back over center.

The solution to this problem embodied in the illustrated latch mechanism is superior to either of these more obvious solutions in that it permits the latch bolt roller M5 to move a substantial distance to the right after the latch bolt I! has reached a cocked position while at the same time permitting the latch bolt II to be tripped by a very light properly directed force.

The extended flattened cam surface 3| is believed to be the primary element in this preferred solution to the problem. It will be apparent upon inspection of Fig. 2 that as soon as the cam roller 32 passes over the hump which divides the cam recess 30 from the flattened cam surface 3|, the cam roller engages the lower portion of the flattened cam surface 3| whereupon the latch bolt I! is cooked. When the cam roller 32 reaches this position the latch bolt roller l8 may still engage the keeper l2 by a substantial margin. In order to permit the latch bolt roller l8 to move further to the right in order to clear the nose of the keeper |2 by a substantial margin, the cam roller 32 may roll along the flattened cam surface 3| any desired distance, limited only by the length of the flattened cam surface.

It will be noted, however, that as the cam roller rolls along the flattened cam surface 3| the actuator 20 will remain substantially motionless.

This means that the cam elements do not move over center and hence no substantial force is required to trip the cam elements such that the latch bolt I1 may be returned to its keeper engaging position illustrated in Fig. 3. Stated differently, the cam elements 32 and 3| have an extended on center position which permits substantial, relative movement of the cam elements after they have reached a toggled or cooked position without passing over center. This arrangement then permits the latch bolt to reach a cocked position while the latch roller I 8 still engages the keeper l 2 and permits the latch bolt roller subsequently to move a substantial distance further in the opening direction without requiring a substantial tripping force.

A similar solution is found in application Serial No. 270,179, referred to above, as to the results obtained. However, in that application the cam roller moves around a cam pin having a flattened surface while in the present disclosure the cam roller 32 moves along an extended cam surface 30 and 3|. The latter arrangement has the advantage that the desired results may be obtained with less accuracy in the formation and positioning of the cam surface which cooperates with the cam roller. Also, slight wearing of the cam surface 30-3l will have relatively less effect upon the operation of the cam elements. Still further one less element is required in the complete structure since, in accordance with the present invention, one cam element, namely the cam surfaces 30 and 3|, may be made an integral part of one element of the latch mechanism. In the illustrated embodiment of the invention, this element is, of course, the actuator. However, it is believed to be obvious that the cam elements might be reversed with the cam roller being arranged on the actuator and the necessary cam surfaces being made an integral part of the latch bolt 11.

In actual practice the flattened cam surface 31 is preferably tilted minutely in a direction such that the cam roller 32 tends to ride upwardly over this cam surface as viewed in Fig. 2. In other words the cam elements do preferably pass very minutely over center. The extent to which the cam elements pass over center, however, is only sufficient to assure that the latch bolt will tend to remain in its cocked position and need not result in the requirement of any substantial tripping force. should be noted that the lightweight spring 35 urges the latch bolt I! in a clockwise direction as previously explained. The force exerted by this spring may be suflicient to maintain the latch bolt I1 in cocked position even though the flattened cam surface 3i is of such shape that the cam elements do not in fact pass even minutely over center. Stated differently the lightweight spring 35 is a supplementary influence along with the spring 22 and the shape of the cam elements in determining what constitutes an over center movement of the cam elements and hence of the latch bolt IT. The spring 35 may be considered as a safety factor to assure maintenance of the latch bolt in its cocked position even though the flattened cam surface 3| is so shaped that movement of the cam roller 32 along its surface induces no rotation whatsoever of the actuator 20.

When the latch mechanism is in the cooked position illustrated in Fig. 2 and the door H is moved toward its closed position, an arm Ha integral with the latch bolt I1 is in a position to strike the head of the keeper l2. This exerts a Further in this connection, it

downward force on the keeper H urging it to rotate in a counterclockwise direction. A very light force is required to so pivot the latch bolt and to cause the cam roller 32 to roll off the flattended cam surface 3|. As the cam roller starts over the hump intermediate the flattened cam surface 3| and the recessed cam surface 30, the force exerted against the roller 32 by the spring 22 acting through the actuator veers around to a direction such that it urges the latch bolt with increasingly greater force toward the keeper engaging position thereof illustrated in Fig. 3.

Th slope of the recessed cam surface adjacent the flattened cam surface 3| is such as to provide a very substantial mechanical advantage in moving the latch bolt roller l8 to the left as the door closely approaches its final closed position. More specifically it will be seen that as the cam roller 32 approaches the position illustrated in Fig. 3, a substantial rotation of the actuator 20 causes a relatively small downward movement of the cam roller. Accordingly, the force of the spring 22 as it reaches the actuator 29 in a counterclockwise direction is greatly multiplied as it is transmitted to the latch bolt I! through the cam roller 32. This substantial force is utilized to advantage in the illustrated application of the invention as it serves to compress a sealing gasket G seen in Fig. 1. Furthermore, this substantial closing force continues to operate to maintain the door in its closed position.

As previously indicated, it is desirable that the latch mechanism permit the door to be slammed shut in the event that the latch mechanism is inadvertentl tripped whil the door is open. This feature is provided for in the illustrated embodiment of the invention through the use of slots 40 in the opposed walls of the latch bolt IT. The pin l8 about which the latch bolt pivots extends through the slots 40 and is located at the right-hand ends thereof when the latch bolt I1 is in either its keeper engaging position illustrated in Fig. 3 or its cocked position illustrated in Fig. 2. It will be noted that the spring tends to maintain the latch bolt I! to the left with respect to the pin I8 and therefore tends to maintain the pin I 8 at the right-hand ends of the slots 40.

In the event that the latch mechanism is inadvertently tripped while the door is open, the latch bolt roller l8 will strike the sloping surface I2a of the keeper when the door II is moved toward its closed position. It will apparent that the force applied by the keeper surface |2a to the latch bolt roller I8 under thes conditions will not drive the cam elements from their normal position illustrated in Fig. 3 to their cocked position illustrated in Fig. 2. This force in fact is in such a direction as to resist such movement of the cam elements.

However, this force is so directed as to urge the latch bolt I! to move downwardly and to the left whereby there is relative movement of the pin l8 away from the right-hand end of the slot toward the left-hand end of the slot 40. Such movement of the latch bolt l1 drives the actuator 20 in a clockwis direction to the position illustrated in Fig. 4, in which figure the latch bolt roller 18 is seen passing upwardly over the nose of the keeper.

The actuator 20 under these conditions assumes substantially the same position as that illustrtaed in Fig. 2 wherein the latch mechanism is in its cocked position. Accordingly, the door must be slammed with approximately the same force as that necessary to release the latch mechanism when it is desired to open the door. More specifically the spring 22 must be distorted to substantially the same extent as is required'in opening the door. The purpose of a cocking latch mechanism is to avoid the necessity of this substantial closing force, the cooking mechanism ordinarily storing the energy expended in releasing the latch mechanism until the latch mechanism is tripped upon closing of the door to release the energy, which then forcibly drives the door to its closed position. However, in the event that a cockable latch mechanism is inadvertently tripped while the door is open it is obviously desirable that the latch mechanism permit th door to be slammed shut even though a substantial closing force may be required. This avoids possible injury of the latch mechanism in the event that the door is slammed toward its closed position after the latch mechanism has inadvertently been tripped.

The latch mechanism described above is a cocking latch which permits slamming of the door with which it is associated in the event that the latch becomes uncooked while such door is open. At the same time the latch mechanism includes novel and improved cam elements whose operation is not critically affected by substantial deviations from what may be considered as the perfect contour, such deviations necessarily resulting from manufacturing tolerances and wear and tear from repeated use. At the same time at least one of the cam surfaces is integral with one of the basic elements of the latch mechanism whereby the latch mechanism is made more reliable and its manufacture simplified.

It will be apparent that the invention may be varied in its physical embodiment without departing from the spirit of the invention, and it is desired, therefore, that the invention be limited only by the scope of the appended claims.

The invention having thus been described, what is claimed and desired to be secured by Letters Patent is:

In a latch mechanism, a supporting frame, a bolt member movable with respect to said frame between a keeper engaging position and a cooked position, a spring biased actautor member movably mounted on said frame for resiliently holding said bolt member in either of said positions, and cam means connecting said bolt member and said actuator member comprising a cam roller rotatably mounted on one of said members and a cam surface forming one edge of the other of said members, said cam surface comprising an extended dwell portion engageable by said roller when said bolt member is in cocked position and a recessed portion for receiving said roller when said bolt member is in said keeper engaging position.

2. In a latch mechanism, a supporting frame, a bolt member pivotally mounted on said frame for movement between a keeper engaging position and a cocked position, an actuator member pivotally mounted on said frame, th pivotal axes of said members being substantially displaced from each other, spring means urging said actuator member to pivot in one direction, and cam means comprising a pair of cooperable cam elements, one of said elements being mounted on said bolt member and one on said actuator member, one of said elements comprising a roller and the other comprising an extended cam surface defining one edge of one of said members, said cam surface having an extended dwell for engaging said roller when said bolt member is in said cocked position, said cam elements, said actuator member and said spring means cooperating to hold said bolt member in said keeper engaging position and said cocked position and to urg said bolt member toward said keeper engaging position when said bolt member lies substantially intermediate said positions.

3. In a latch mechanism, a supporting frame, a bolt member pivotally mounted on said frame for movement between a keeper engaging position and a cooked position, an actuator member pivotally mounted on said frame, the pivotal axes of said members being substantially displaced from each other, a coil spring circling the pivotal axis of said actuator member and urging said actuator member to pivot in one direction, and cam means comprising a pair of cooperable cam elements, one of said elements being mounted on said bolt member and one on said actuator member, one of said cam elements comprising a roller, the other of said cam elements comprising an extended cam surface forming one edge of one of said members, said cam elements, said actuator member and said spring cooperating to hold said bolt member in said keeper engaging position and said cocked position and to urge said bolt member toward said keeper engaging position when said bolt member lies substantially intermediate said positions.

4. In a latch mechanism, a supporting frame, a bolt member pivotably mounted on said frame for movement between a keeper engaging position and a cooked position, an actuator member pivotally mounted on said frame, the pivotal axes of said members being substantially displaced from each other, a coil spring circling the pivotal axis of said actuator member and urging said actuator member to pivot in one direction, and cam means comprising a pair of cooperable cam elements, one of said elements being mounted on said bolt member and one on said actuator member, one of said cam elements comprising a roller, the other of said cam elements comprising an extended cam surface forming one edge of one of said members and having a flattened surface engaging said roller when said bolt member is in said cocked position, said cam elements, said actuator member and said spring cooperating to hold said bolt member in said keeper engaging position and said cocked position and to urge said bolt member toward said keeper engaging position when said bolt member lies substantially intermediate said positions.

5. In a latch mechanism, a supporting frame, a bolt member mounted on said frame, said bolt member being pivotable with respect to said frame between a keeper engaging position and a cooked position and slidable with respect to said frame between said keeper engaging position and a keeper by-passing position, an actuator member mounted on said frame, said actuator member being pivotable with respect to said frame between a normal position corresponding to said keeper engaging position of said bolt member and an energized position corresponding substantially to both said'cocked position and said keeper by-passing position of said bolt member, the pivotal axes of said members being substantially displaced from each other. a coil spring circling the pivotal axis of said actuator member and urging said actuator member to pivot toward said normal position, and cam means comprising a pair of cooperable cam elements, one of said elements being mounted on said bolt member and one on said actuator member, said cam element on said bolt member comprising a roller, said cam element on said actuator member comprising an extended cam surface forming one edge of said actuator member, said actuator member and said spring operating through said cam elements to hold said bolt member in said keeper engaging position and said cocked position, to urge said bolt member toward said keeper engaging position when said bolt member lies substantially intermediate said last-mentioned positions, and to urge said bolt member from said keeper by-passing position toward said keeper engaging position.

6. In a latch mechanism, a, supporting frame, a bolt member mounted on said frame, said bolt member being pivotable with respect to said frame between a keeper engaging position and a cocked position and slidable with respect to said frame between said keeper engaging posi tion and a keeper by-passing position, an actuator member mounted on said frame, said actuator member being pivotable with respect to said frame a normal position corresponding to said keeper engaging position of said bolt member and an energized position corresponding substantially to both said cocked position and said keeper by-passing position of said bolt member, the pivotal axes of said members being substantially displaced from each other, a coil spring circling the pivotal axis of said actuator member and urging said actuator member to pivot toward said normal position, and cam means comprising a pair of cooperable cam elements, one of said elements being mounted on said bolt member and one on said actuator member, said cam element on said bolt member comprising a roller, said cam element on said actuator member comprising an extended cam surface forming one edge of said actuator member and having a dwell for engaging said roller when said bolt member is in said cocked position, said actuator member and said spring operating through said cam elements to hold said bolt member in said keeper engaging position and said cocked position, to urge said bolt member toward said keeper engaging position when said bolt member lies substantially intermediate said lastmentioned positions, and to urge said bolt member from said keeper by-passing position toward said keeper engaging position.

7. In a latch mechanism, a supporting frame, a bolt member pivotably mounted on said frame for movement between a keeper engaging position and a cooked position, an actuator member pivotally mounted on said frame, the pivotal axes of said members being substantially displaced from each other, spring means urging said actuator member to pivot in one direction, and cam means comprising a pair of cooperable cam elements, one of said elements comprising a roller mounted on said bolt member, the other of said elements comprising an edge of said actuator member forming an extended cam surface having a dwell for engaging said roller when said bolt member is in said cocked position, said cam elements, said actuator member and said spring means cooperating to hold said bolt member in said keeper engaging position and said cocked position and to urge said bolt member toward said keeper engaging position when said bolt member lies substantially intermediate said position.

, References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,385,961 Anderson Oct. 2, 1945 2,444,180 Anderson June 29, 1948 2,445,709 Curtiss July 20, 1948 2,546,333 Curtiss Mar. 27, 1951 

